1. Field of the Invention
The present invention relates to the field of backlight module of liquid crystal display, and in particular to a design of a light guide plate of a side-edge backlight module.
2. The Related Arts
Liquid crystal display (LCD) has a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and is thus widely used. Most of the LCDs that are currently available in the market are backlighting LCDs, which comprise a liquid crystal panel and a backlight module. The operation principle of the liquid crystal panel is that liquid crystal molecules are interposed between two parallel glass substrates and a plurality of vertical and horizontal fine electrical wires is arranged between the two glass substrates, whereby the liquid crystal molecules are controlled to change direction by application of electricity in order to refract light emitting from the backlight module for generating images. Since the liquid crystal panel itself does not emit light, light must be provided by the backlight module in order to normally display images. Thus, the backlight module is one of the key components of an LCD. The backlight module can be classified in two types, namely side-edge backlight module and direct backlight module, according to the position where light gets incident. The direct backlight module arranges a light source, such as a cold cathode fluorescent lamp (CCFL) or a light-emitting diode (LED) at the back side of the liquid crystal panel to form a planar light source that directly provides lighting to the liquid crystal panel. The side-edge backlight module arranges a backlight source of LED light bar at an edge of a back panel to be located rearward of one side of the liquid crystal panel. The LED light bar emits light that enters a light guide plate (LGP) through a light incident face of the light guide plate and is projected out through a light exit face of the light guide plate, after being reflected and diffused, to thereby transmit through an optic film assembly and form a planar light source for the liquid crystal display panel.
Brightness sectioning and independent control of the backlighting of a backlight module is the basis of various techniques, such as local dimming, scanning 3D, improvement of dynamic contrast, and power saving. In a traditional side-edge backlight module, light dispersion caused by the light guide plate makes the results of these techniques of local dimming, scanning 3D, improvement of dynamic contrast, and power saving poor. To overcome such a problem, the light guide plate is designed in such a way that the light guide plate is formed with microstructures thereon. However, the conventional microstructure-carried light guide plate is deficient in showing poor light isolation and poor yield, being poor for mass production, and suffering severe warping and deformation after absorbing humidity. In addition, the cost is higher than regular light guide plate by at least 25%.